Dutch researchers looked at 500 people who suffered a stroke caused by blocked blood flow to the brain -- what's known as an ischemic stroke, the most common form.

About half of the patients received intra-arterial treatment (IAT), which involves inserting a catheter into an artery to either remove the clot, to deliver clot-busting drugs near the site of the blockage, or both. The other patients did not receive IAT.

The study found that the average amount of time needed between the onset of a stroke and the moment the patient first received the catheter was about four hours and 20 minutes, and the average time it took for blood flow to be restored to the brain was five hours and 40 minutes.

There was a 6 percent lower chance of a good outcome for patients for every hour of delay in restoring blood flow to the brain, concluded a team led by Dr. Diederik Dippel, of Erasmus MC University Medical Center in Rotterdam.

"This study highlights the critical importance of reducing delays in time to IAT for patients with acute ischemic stroke," they wrote. "Our findings imply that patients with acute ischemic stroke should undergo immediate diagnostic workup and IAT."

One expert in the United States agreed.

"Stroke is a medical emergency, and approximately 2 million brain cells are lost every minute that it goes untreated," said Dr. Sanskriti Mishra, stroke fellow at North Shore-LIJ's Cushing Neuroscience Institute in Manhasset, N.Y.

"It is essential that people are aware of the symptoms of a stroke -- such as sudden onset of facial droop, arm weakness, speech difficulty -- so they can seek medical care urgently," she said.

"This study shows that delay in treatment aimed at restoring blood flow in the brain reduces chances of recovery from stroke," Mishra said. "Patients with stroke should undergo an immediate evaluation for lifesaving procedures if their arteries are blocked by a blood clot."